Patient lifts are generally known in the health care industry. Such patient lifts help a caregiver to transfer a patient from one place to another such as bed to chair, toilet, stretcher, and so on.
There are primarily two types of such patient lifts, arc lifts and column lifts. Examples of these are shown in FIGS. 1 and 2 respectively. These lifts typically include a support arm or boom and a spreader bar or cradle supported by the boom. A sling for lifting a patient is hung from the spreader bar or cradle.
The difference between an arc lift and a column lift is mostly in the movement of the boom. The boom of an arc lift is fixed at one point to a mast. The movement of the boom is an arc around this fixed point. The boom of a column lift glides vertically along a mast. Both type of lifts are compatible with different types of spreader bars that answer different needs.
The problem with arc lifts is that, in order for the spreader bar to stay parallel to the floor during the full lifting stroke, the connection point needs to allow a swinging movement. This problem is not seen with column lifters because the spreader bar is maintained parallel to the floor by the boom which moves along the mast vertically and not in an arc motion.
Although this swinging movement is necessary, it can be dangerous. As can be seen in FIG. 3, swinging of the arc boom will tend to cause the spreader bar to swing outwardly and towards the patient. Therefore, when the care worker approaches the patient, he or she needs to be very careful not to hit the patient with the spreader bar.